Storage-battery-charging system



E. F. ANDREWS.

STORAGE BATTERY CHARGING SYSTEM. APPLIATIoN man 1Au.a,1911.

1,356,753. Patented 00u 26,1920.

DHA/Pd HMQREMS.

UNITED STATES PATENT oFFicE.

, l EDWARD F. ANDREWS, 0F CHICAGO, ILLINOIS.

STORAGE-BATTERY-CHARGING SYSTEM.

Application med January B, 1817. Serial No, 141,153.

To @Il i12/trom it may concern Bc it known that I, Enwaun l1`. ANniunvs,aV citizen of the United States, residing at Chicago, in the county ofCook and State of Illinois, have invented a certain new and usefulIinprovcment'iii Storageattei'ylfhargng Systems, of which the fol lowingis a full, clear, concise, and exact description.

My invention relates to .improvements in storage battery chargingsystems.

It relates more particularly to means and a method fdr bringing thestorage battery to a conditiohfof'full charge without objectionableovercharge, and is especially applicable to isolated generating plantsof the type used in rural districts, although not limited thereto.

Heretofore,much difficulty has been en countered by the users ofgenerating plants of this type, owing either to the complicated anddelicate .apparatiis employed to control the charging of the storagebatteries, or to the fact that considerable tei-.liniaal knowledge wasnecessary on the part of the user in order to obtain 'satisfactoryresults. oftentimes, the life cfa battery is materiallyr shortened andthe efficiency of the amount of fuel in the reservoir, the hy rometerand the fuel gage being so calibrated vas to indicate readily to theoperator how much fuel should be put into the reservoir to enable theengine to drive the generator for a length of time just sulficiently tofully charge the batt/ery, at the end of which time the stopping of theengine for lack of fuel prevents further charging.

Further objects and advantages of the invention will be apparent fromthe following detailed description of the embodiment of ,the inventionshown in the accompanying drawings. It is to be understood that thedisclosure is for the purpose of illustration only, and not as definingthe limits of the invention.

In the drawings is -disclosed a diafrrammatic view illustrating a systemern dying my invention, wherein 1 designates a single unit power plantcomprising anl eleotric generator A and a prime mover preferwhole plantgreatlyreducel either-by undercharging or overcharging, due to thenopei'ators lack of knowledge of such complicated apparatus, or tothefailure of suoli apparatus to properly perform its function.

he general object of the present invention is to provide means and ametihod whereby the dfiiculties heretofore expericnced in thecharging'of storage batteries are largely overcome.

A further object of the present invention .is to'pi'ovide a cheap,simple, and easily operated means whereby the storage battery of anisolated electric lighting plant can be brought up to the propercondition off charge, without uhdue overcharge'.`

A {urth r Objectis to provide a system of the type described whereby thebattery of suclia plant maybe. properly charged with a minimum ofattention from the operator.

These objects are attained by providing a generator, an `internalcombustion engine adapted to drive the same, a fuel reservoir ably inthe form of an internal `combustion engine B,"coupled to' and adapted todrive said generator A. Connected in series with the generator A of thepower plant 1 is a storage battery 2, preferably, although notnecessarily, provided with a pilot oeil 3, which is in turn providedwith a h drometer 4 of any suitable type, ada ted tooat in theelectrolyte of said pilot ce l for the purpose v of indicating to theattendant the condition of charge of the battery. To this end, the upperportion of the hydrometer s cali brated as shown at 5, so ,that thedegree of charge or discharge of the batter may be readil ascertained.It is a we l known fact t at the specific gravity ofthe electio lytedecreases as the battery discharges, ani

that conversely, the specific gravity iii-- creases as the charge of thebattery increases. Thus it will he seen that the hydrometer reading willgive a close approximation of the condition of chargr of the battery,

It is'obvious that instead of thehydrometer and pilot cell combination,illustrated in the drawings, a syringe hydrometer may be used, intowhich electrolyte may be drawn from any one of the battery cells, inorder to ascertain the condition of charge of the batte ghe prime movecofthe power plant 1 is suaplied with fuel from a reservoir 6 of anyesired shape or size. Positioned within the reservoir is a float T shownprovided With a Suitable gage 8,- the registration of the calibrationsof the gage with an indicator 9 mounted on the reservoir, servingv toindicate the fuel level within the reservoir. The VGoat 7 and indicatingmechanism 8 and Hrmay be of any preferred construction. As shown' in thedravvinfY however, an opening' is provided in the top wall of thereservoir through which the gage 8 is free to reciprocate according tothe rise or fall of the fuel and pointers 9 are shown ada ptcd toregister' with the calibrations on the gage 8.

The fuel reservoir 6 is preferably of such a size that when filled withfue] and the prime mover B started, it will keep thil gen erator runningjust a sullicient length of time to effect the proper and coinplekA charg ing without undue orerrharge of the baitery, provided that thebattery was fully discharged at the time the charging oper-- ation wasstarted. The proper size oi' the reservoir, in the first instance, maybe readily ascertained by suitable tests. It is also preferable that thereservoir 6 be pro vided with a sump 18, into which the fuel` feed pipe19 dips, in order to )rovidea more definite level at which the fuelsupply to the en ine ceases. This, however, is not essentia A furtherfeature of the invention is the arrangement of the calibrations on thefuel age 8 to facilitate their being read in ,conf ]unction with thereading of the hydrome ter, so that the hydronieter reading indicates tothe attendant not only the condition of the charge or discharge oi' theliaitery, but also the amount of fuel necessary to be placed in thereservoir 6 to fully charge the battery, from any state of discharge asindicated by the hydrometer. One means for accomplishing this result isshown in the drawings, but it is obvious that the result may be attainedin various other ways, and hence I do not4 wish to be limited to theparticular structural features shown. As shown in the drawings, thehydrometer calibrations run from 1 to 10,'startin at the top, andindicate the condition o chere or discharge of the battery, while the eaibrations on the fuel gage 8 run from l to 10, starting at the bottom,andiindieate the amount of fuel in the reservoir. As previously pointedout, the specific gravity of 'the electrolyte increases as the chargeincreases; hence as current is supplied by the generator integree to thebattery and the char ing rogressea, the spcciiic gravity of the eectro-yte is?? creased and the hydrometer 4 is causedto rise. At thesame time, fuel is bein'gdriuvn4 from the reservoir 6 by theprimei'nidvi and the fuel gage thereforvgradually' falls.

state of discharge it may' happen tpfbe 'in.`

The fuel tank i desired may'be so proportioned and the hydronietergraduated that instead of bringing t e battery just to full charge withthe amount of fuel put into the tank, a quantity of fuel niay )e put inwhich will give any desired amount of overcharge to the battery' at eachfilling of the tank.

lt i5 well known that'iiydronieterreadings sary with temperature. The.liydrometer used with this system may haver'f v"readings corrected fortemperature in various ways well known in the art. A compensatinghydrometer may also be used which gives the correct* reading at anytemperature without correction.

The work circuit is shown at 10, in the form of a lamp circuit, -aswitch 11 being provided to control the same. The generator ispreferably shunt-wound, but not` necessarily so. is shown at 12, itsAfunction being to prevent any discharge of battery current through the`generator when the generator voltage is less than that of the batteryexcept when starti at which time the generator is operate as a motor inorder to start-the engine B. Although the ignition system of the engineforms no part of itie present invention, a circuit suitable folgt epurpose is illustrated in the draiivings"Goth sistifig of a primarycircuit 13, ineludinga primary coil i4, together with an interruptor l5and a condenser 16 in parallel with said interi-opter, this primarycircuit being connected across the battery terminals through theunderload circuit breaker 12. A^"sec ondarv circuit is also shown,including a' secondary coil l7suitably-connected to the salark plug andto the ground. W'henc'ver the underload circuit breaker opens thecireuit from the generator to thebatteryfthe primary circuit 13 of theignition systemI is also opened, thereby causingjhe engineto stop. l

The charging system herein described is and fuel age soV An. underloadcircuit 4breaker its the generator constituting the onlycontinuously;operating governing means. As the power output of an engineunder these conditions is approximately constant, the power .or wattoutput of the generator is also approxixvnately constant, and if astorage battery-isconnected across-the terminals of the enerator, theamount of current'flowing into ,thebattery will be determined by thecgunt'er E. M. of the battery. When the batteryis low in charge and itsvoltage is low, t e charging current will be high, and towardthe end ofth'echarge as the battery voltage increases, the charging current willdecrease, the watts or electrical energy consumed .remaining the4 same.Under these conditions it will appear that when the total electricalenergy rodiioed by the generating unit is being used) to charge thebattery, the factors to be'oonsidered in bringing the battery :up tofull charge without undue overchar e are first, the conditionof chargeof the attery atv the time charging is commencedand, second, the lengthof time that thefpriine'mover and generator must be run in order 3obring the battery up to the de sired con ition.

It obvious, however, that instead of the particulary system of governingdescribed heitiman'y suitable governing means may be employed. Forinstance, it may be desirable tosoarrange the prime mover that it can bemade ,to ive .less th`an,its normal power output.. This may be desirablein order to reducetbecharging rate of the storage battery toward the endof its charge` The decrease in power of the prime mover, whicheft'e'ct's a corresponding decrease in the electricalv output or thegenerator, may be brought about by hand adjustment or automatically inany well known manner. This change of output has noetect on theprinciple of operation of this s stein, because if the power isdecreased, t us requiring a longer run of the generator to charge thestorage batteries, the fuel consumption is also decreased, thusrequiring similarly longer time to exhaust the supply of fuel in thetank. y 1

From the foregoing descriptiomthe operation of the system will bereadily understood. Assuming that the hydrometer reading is at 7, thisindicates to the attendant that the battery is approximately 3() percent. discharged and also that it is necessary to fill the reservoiruntil the fuel ga re registers 7, in order that theengine, a ter it isvstartedfshall drive the'generator just long enough to fully charge tuebattery, at the end-of which time it` will stop for 'lack of fuel, thusautomatically preventing the battery from being unduly overchargedj`This operation presupposes that all of the electrical energy producedbythe 'generator is 'available for4 charging the battery. When `ywill bedivided between the battery the lamps or other translating devices arebeing used on the. circuit 10 while the batterv is being charged, thegenerator output circuit and the work circuit.

It will appear from this consideration. that if the hydi'ometer readingis taken and the proper amount of fueI put into the furl tank, to effectthe complete charging of the battery from the point of charge indicatedby the hydrometer, and if, during the charging operation, current istaken from the generator circuit which is consumed otherwise than incharging the battery, the said battery will not be fully charged whenthe prime moverstops for lack of fuel. Under these conditions, it willbe necessary to read the hydrometer a second time and to refill the fuelreservoir until the reading of the fuel gage coresponds with the readingof the liydroincter and to restart the engine B in order to effect thecomplete charging of the battery. However, such service as this is theexception, rather than the rule, as the usci-s of isolated lightingplants generally prefer to chai-ge their batteries in the daytime-andderive current for their lights and other translating devices `in theevening from the battery alone. If for any other reason than thatmentioned above, such as ovm-discharge of the battery or improperworking of the engine, the battery does not come up to full charge withthe amount of fuel indicated by the hydioineter reading, it can beeasily brought to the desired condition by takingr a second hydronieteireading and refilling the tank as above described.

AIt is not essential that the fuel tank be large. enough to run theengine for sufiicient time to completely charge the storage battery froma condition of entire discharge. For instance, in `charging largebatteries with a small engine. it might be desirable to pro vide a tankholding only half the fuel necessary for complete charging. lt might beneces sary to do this to comply with the Underwriters requirements,which stipulate that not more than one gallon of gasolenc may be kept.in certain buildings without raising the fire insurance rates. In suchcases it is necessairy only to take the hydroineter reading each timethe fuel becomes exhausted and to fill the tank to the point indicatedby the hydrometer, if possible. If this point be beyond the capacity ofthe tank, it is obvious that the tank must be completely filled andtlien refilled after the first instalment 4of fuel is exhausted, inorder to completely charge the battery. It is obvious, however, that theprinciple of operation of this system is the same no matter how manytimes the tank must be filled to completely charg the battery. n

It is obvious that this invention is not limited in its scope toelectric lighting associated with said battery, a fuel risservoirvadapted to supply fuel to said engine, a gagefor said reservoir, saidhydrometer bein sorelated to said gage as to indicate the rea ing whichthe gage should be made to give by the fuel in said reservoir in orderto fully charge said battery.

2. A system of the class described, comf prising a single unit powerplant, a storage battery, the pilot cell of which is provided with ahydromter, anda fuel tank for said power plant, said hydrometer beingcalibrated 1n 4such wise that a reading thereof,

indicates the amount of fuel to be placed in said tank to fully chargesaid battery;

3. The combination with a. single unit power plant, comprising agenerator, and a prime mover, of a storage battery connected to saidgenerator adapted to receive its charge therefrom, a fuel reservoiradapted to supply fuel to said prime mover, and indicators coperatingwith said battery and said reservoir adapted to indicate the amount offuel necessary tobe placed in said reservoir tofully charge said batterywithout undue overcharge. 2

4. The combination with an electric generator and an internal combustionengine adapted to drive the same, of a storage battery connected withsaid generator and adapted to receive its charge therefrom, a fuelreservoir for said internal combustion engine, and a hydrometer forYdetermining the condition of the charge of said storage battery, saidhydrometer being provided with means for indicating the amount ofuelnecessary to be placed in said reservoir ,to operate the said 'generatorby means of said engine for a proper length of time to effect thecomplete charging of said battery, at the end of which time said enginewill' stop for 56 lack of fuel, thus preventing undue over- L chargingof said battery.

5. A system of the class described, com prising a power plant, a storagebattery connected thereto, a fuel reservoir adapted to 6U supply fueltosaid power plant, and means to determine the amount of fuel necessary.to fully charge said battery.

An isolated electric generating system, comprising a. generator, aninternal combustion engine for driving the same, a storagebattery'connected to said generator, a fuel reservoir for said engine,'a hydrometer vfor indicating the state of charge of said battery andhaving indications thereon, and a float in said reservoir also having'indications thereon, said hydrometer and float indications being sorelated that it is onl necessary to read said hydrometer and add el tosaid reservoir until the iloat indications coincide with thecorresponding indications on the hydrometer, in order to fully chargethe battery without unduly overcharging it.

7. The method of insuring .the charging of a storage battery to adesired state of Acharge from any` particular. state .of dis-` charge ina system in which the battery is A charged by' a generator driven by aninternal combustion engine, which method comprises predetermining theamount of` fuel necessary to'rsupply the deficiency of charge andsupplying only this amount of fuel to the engine.,

8.A The combination with a battery charging system comprising agenerator, alprime mover, and a battery connected with said generatorand adapted to receive its charge therefrom, of a hydrometer for saidbattery,

said hydrometer'being calibrated in terms to indicate the amount of fuelwhich will be reciired to operate said prime mover just a su cientlength of time to fully charge said battery regardless of its degree ofdischarge.

9. The combinationwith a battery charging system comprising a generator,a prime mover, and a battery connected with said generator and adaptedto receiveits charge therefrom, "of means associated with'said batteryfor indicatingsubstantially' the ex-r' lact amount of fuel necessary tooperatesaid prime mover to effect a completeV charging of said battery.

10. The combination with anelectric generator and an internal combustionen ine y adapted to drive the same, of a storage' at# tery connectedwith said generator and adapted to receive its charge therefrom, a fuelreservoir for said internal combustion engine, and means associated withsaid battery for indicating the amount of fuel required to be laced insaid reservoir to f ully charge said attery, the amount of fuelindicated by said means varying according to the condition of dischargeof the battery and being such an amount that the same will be completelyexhausted when the battery has reachled a fully charged condition,thereby causing said engine to sto and preventing undue overcharging ofsai batte y.

11. The combination with a single unit` power plant, comprising agenerator, and a prime mover, of a storage battery connected to saidgenerator adapted to receive its charge therefrom, a fuel reservoir dated to supply fuel to said prime movgr, an indicators coperatingwitlifshid batteyand las said vreservoir adapted to 'indicate the powerplant, said hydrometer being caliamount of fuel which will be requiredto brated in such Wise there reading thereof 10 fully charge saidbattery without undue indicates the amount of fuel to be suppliedovercharge. r to said power plant from said tank in order 5 12. A systemof the class described, comto fully charge said battery. f

rising a single unit power plant, a storage In Witness whereof Ihereunto subscribe attery, the pilot cell of which is provided my name.

with a hydrometer, ande. fuel tank for said EDWARD F. ANDREWS.

